This invention relates to a programmable lead pull method and apparatus for use with a stator winding machine and particularly for use with stator winding machines used to wind field coils, especially for 2-pole stators.
In the manufacture of 2-pole stators, a common practice is to position a stator to be wound in a winding station with its longitudinal axis aligned with the axis of oscillation and reciprocation of a winding shuttle that draws wires from sources of wire under tension and winds the wires into coils around the stator pole pieces. There are typically four wire clamps located in fixed relation to the stator being wound into which the stator start and finish leads are inserted by a lead pull assembly that includes a pair of wire grippers, one being associated with each stator coil. In operation, after a stator is wound, the wire clamps are moved with the freshly wound stator out of the winding station and the wire grippers, which remain in the area of the winding station, hold the free ends of the wires exiting from the winding shuttle in predetermined positions. After the next unwound stator to be wound is located in the winding station, and often after the winding of coils on the unwound stator is commenced, the lead pull grippers are manipulated by mechanical means to insert the wire ends gripped by them into a pair of the wire clamps fixed relative to the unwound stator.
After the coils are fully wound, the wire grippers are again manipulated, this time to clampingly engage the segments of the wires extending from the newly wound coils to the winding shuttle and to insert the wire segments into another pair of wire clamps fixed relative to the freshly wound stator. In some cases the coils have tap leads in addition to the start and finish leads. In the past, the wire grippers have been used to pull the tap leads, but the tap leads were normally pulled out of the way and not securely clamped, the wire clamps normally being used only for the start and finish coil leads.
Older stator winding machines were typically dedicated to the winding of stators having but one configuration or a narrow range of configurations. In order to be used to wind stators having differing configurations, costly and time-consuming retooling or other change-over steps had to be taken. There is an ever increasing need to provide stator winding machines capable of being rapidly and inexpensively set up to wind stators of various different configurations. There is also a continuous need for improvements in the simplicity, cost, speed of operation, and reliability of stator winding machines. Of course, the same needs apply to lead pull apparatus. In addition, lead pull assemblies must also be sufficiently compact that they do not interfere with the other functions of the stator winding machine with which they are used. Compactness is an important factor, particularly because there is a usually a small space in the area of the winding head and the stator being wound within which a lead pull assembly is located.
An object of this invention is to provide a lead pull method and apparatus for use with a stator winding machine which is flexible so that it can be quickly set up for use with stators of various different configurations and which also meets the foregoing criteria of simplicity, low cost, high operating speeds, high reliability, and compactness.
In accordance with this invention a lead pull assembly is provided which comprises a pair of wire grippers, one for each of the stator coils, mounted on a pair of carriages that are supported for movement along mutually spaced and parallel paths located, respectively, above and below, the axis of oscillation and reciprocation of a winding shuttle. (Here it should be noted that relative terms such as "above", "below", "front", and "rear" are used in a relative and not an absolute sense herein unless the context indicates otherwise.) The carriages are driven back and forth along their respective paths in mutually opposite directions by a drive motor connected by timing belts to a pair of drive screws, one for each of the carriages. The wire grippers are mounted on the carriages by a first frame immovably affixed to its carriage and a second frame pivotally mounted on said first frame that may be pivoted about an axis parallel to the axis of movement of the carriage by operation of an air actuator mounted on the first frame. A second air actuator mounted on the pivotal frame opens and closes the wire gripper jaws and may also operate a cutting blade in a manner known in the art.
The lead pull apparatus of this invention is disclosed as part of a stator winding machine having a turret plate mounted for rotation about a vertical axis extending centrally therethrough, and plural stator clamp mechanisms mounted at spaced locations around the periphery of the turret plate, each of which mechanisms clamps a stator to the turret plate. For reasons which will become apparent, each stator is clamped to the turret plate with its center axis extending horizontally and substantially perpendicularly with respect to the vertical axis of rotation of the turret member and with the end face of the stator most remote from the vertical axis of the turret plate held in a vertical orientation spaced a fixed horizontal distance from such vertical axis. The stator is positioned on a seat adjacent each of the clamp mechanisms which may include a replaceable spacer for positioning the clamped stators at a proper height.
A wire clamp assembly is mounted on the turret plate adjacent each of the stator clamp mechanisms. Each wire clamp assembly preferably has programmable, air operated wire clamps adapted to temporarily hold coil lead wires extending from coils wound on a stator being wound.
The turret member is repeatedly indexed in one direction about its vertical center axis to repeatedly sequentially move each of the stator clamp mechanisms to a load/unload station, a winding station, a coil lead terminating station, and then back to the load/unload station. In the presently preferred embodiment, the turret has four stator clamp mechanisms, located 90 degrees apart around the periphery of the turret plate, one for each of the above-mentioned stations and an additional one which is accommodated by an idle station between the load/unload station and the winding station. However, it would be possible to utilize a 3 station turret plate in a winding machine which would not have an idle station.
At the load/unload station, a newly wound stator is removed from the turret plate and replaced by an unwound stator. Subsequently, the unwound stator is moved by an index of the turret plate to the winding station. Located adjacent the winding station is a winding head having a winding shuttle or ram that reciprocates and oscillates about a fixed horizontal axis to draw two or more wires from sources of wire under tension to wind the wires into coils about the stator poles. In advance of the operation of the winding head, two pairs of winding forms are connected to the unwound stator at the winding station, and a pair of wires extending from the wire sources and held by wire grippers are inserted by movement of the wire grippers into a pair of the wire clamps supported on the turret plate. Coils of wire are then wound on the unwound stator by operation of the winding head. At the conclusion of the winding operation, the wire portions leading from the coils to the winding shuttle are gripped by the wire grippers to form coil finish lead wires extending from the coils, which are positioned in other wire clamps on the turret plate. Wire cutting mechanisms associated with the wire grippers cut the finish leads, now clamped to the turret plate, free from the wire grippers so that the newly wound stator is completely severed from the winding head. The stator may then be indexed by rotation of the turret plate to the wire terminating station at which the start and finish leads are removed from the wire clamps and at least temporarily connected to terminals on the stator by a robot or other suitable mechanism. Accordingly, when the newly wound stator arrives at the load/unload station, it may be simply unclamped from the turret plate and removed. The foregoing operations are repeated to continuously wind stators.
Preferably, in addition to the programmable control of lead pull assemblies of this invention, the stator clamp mechanisms and the stator seats and spacers are quickly replaceable to accommodate stators having different stack diameters, the winding form handling and locking mechanisms are capable of accommodating stators having different stack heights, and the winding head is programmably movable for accommodating stators having different stack heights.
Although the lead pull method and apparatus of this invention is especially advantageous for use with the stator winding machine described above and is further described below, it will be apparent that it may be used in various other stator winding machines.